We had a situation in our last campaign where a dragon was flying over our heads and causing us much harm. Our controller cast Storm Pillar to block him at one point, which sparked a discussion between us and our DM about the height of said pillar.

The caster's player suggested it would be the same height as his range.

I thought it would be infinitely tall, as it occupies one square (2D, mapped to 3D, would be infinitely tall if it occupies the entire 2D space).

Our DM thought it would be one cube tall (5'x5'x5').

The ceiling was approximately 50' from the ground.

What is the right answer? How tall are such things? Could a dragon fly over them?

(Our DM allowed us to consider it as reaching the ceiling, thereby blocking the dragon from slaying our heroes.)

Storm pillar discussion on the forums.. Have... fun? reading 5 pages of arguing, at least that will save us some time with answers here...
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Brian Ballsun-Stanton♦Feb 14 '12 at 13:55

Thanks for correcting the title, Jason! I'm not quite ready to select an answer, as there appears to be just too much ambiguity involved and I haven't seen a concrete answer with citations.
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RobFeb 15 '12 at 18:58

4 Answers
4

I'm going to assume you mean Storm Pillar since I can't find a Pillar or Lightning in the compendium. Based on the rules as worded, this ability would create a 1x1x1 cube, extending only 1 square (5 feet) over the square it is placed in.

We normally think of a pillar as an object much taller than it is wide, but since there is no mention of its height, it defaults to the same as any other area ability or zone. It certainly doesn't extend infinitely high, but I understand your DM allowing it to hinder the dragon if you had no other way of stopping it.

This is a DM call, as the rules are somewhat ambiguous. Without that ambiguity being cleared, there are two conflicting parts:

Arcane Power (and the online compendium) indicate that it "occupies" 1 square. Characters also occupy one square, and although they don't exactly fill the whole 5x5x5 (and could be taller), they block enemy movement within that space.

A Pillar is defined as being tall, not cubic, so it is implied that it is more than a single square, but there is no specified height to circumference ratio.

I hate to answer my own question, but given the already-posted answers, I think I need to combine them.

It appears the ultimate answer is "it is up to the DM".

Given that, the DM might take one or two stances, both equally legitimate:

The pillar should default to one cube in size, as no height is specified.

The pillar is of an arbitrary height, as it is said to occupy one square (a 2-dimentional measurement).

Other objects that occupy one square are assumed to occupy a 5'x5'x5' cube, but such a measurement doesn't necessarily map via common sense to such a cube for a storm pillar, defined as a column of lightening.

Effect: You conjure a pillar of crackling energy in an
unoccupied square within range. The pillar occupies 1 square and lasts
until the end of your next turn. Each enemy that moves into a square
adjacent to the pillar on its turn takes 1d6 + your Intelligence
modifier lightning damage. Level 21: 2d6 + Intelligence modifier
lightning damage.

The way I read this power is as follows.
The caster creates a taller than wide column of lightning. This Column of lightning does not stand still, but rather moves back and forth, being attracted to enemies, and lashing out at them if they go near it. For this reason is "occupies" one square.

Now, for the Dragon, we need to look at the flying rules, and see if two flying creatures, or a flying creature and a non-flying creature can occupy the same "square".

The Entry for flying has the following:

Flying Flight Some creatures have the innate ability to fly, whereas
others gain the ability through powers, magic items, and the like. The
rules for flight in the DUNGEONS & DRAGONS game stress abstraction and
simplicity over simulation. In real life, a flying creature’s ability
to turn, the speed it must maintain to stay aloft, and other factors
put a strict limit on flight. In the game, flying creatures face far
fewer limitations.

FLIGHT Flight follows the basic movement rules, with the following
clarifications. (Emphasis mine)

Fly Speed: To fly, a creature takes the walk, run, or charge action but uses its
fly speed in place of its walking speed. A creature that has a fly speed can also shift
and take other move actions, as appropriate, while flying.

Moving Up and Down: While flying, a creature can move straight up, straight down,
or diagonally up or down. There is no additional cost for moving up or down.

Falling Prone: If a creature falls prone while it is flying, it falls. This means
a flying creature falls when it becomes unconscious or suffers any other effect that
knocks it prone. The creature isn’t actually prone until it lands and takes falling
damage.

Remaining in the Air: A flying creature does not need to take any particular action
to remain aloft; the creature is assumed to be flying as it fights, moves, and takes
other actions. However, a flying creature falls the instant it is stunned, unless it can
hover.

Landing: If a creature flies to a surface it can hold onto or rest on, the
creature can land safely.

Terrain: Terrain on the ground does not affect a flying creature if the terrain
isn’t tall enough to reach it. Because of this rule, flying creatures can easily bypass
typical difficult terrain, such as a patch of ice on the ground. Aerial terrain can
affect flying creatures.

Since it does not specify that two creatures who are flying may occupy the same space, or a flying creature can not occupy the same space as another creature (the way a swarm can), it seems to me that in this case, the Pillar reaches the height of the space that it occupies, and in this case that means the ceiling.

The pillar would occupy the space for purposes of movement even to flying creatures, as it occupies the entire square.

I believe the argument that it is as tall as it's range is not correct. And I think the argument that it only takes up 5 feet of height it also incorrect. There are plenty of PCs and monsters that are over 5 feet tall, and still only occupy 1 square.
Since the DnD game map is really 2.5 dimensions, and not 3, the effective height of the pillar is "infinite", or rather, it goes as far up as the space that the ground represents, goes up.

This is incorrect. the "pillar" occupies 1 square so its a 5x5x5 cube. The D&D world is kind of like minecraft, composed of distinct cubes. a "square" is actually a cube. thus 2 creatures may share the same X and Y locations but be in different squares because they are in different blocks on the z axis.
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wax eagleFeb 14 '12 at 13:35

You can't put two characters on the same square, and I can't find any indication that you are allowed to have a flying creature in the same space (x,y coordinate) on your map as a non-flying creature. Also, a pillar is not an area effect, nor a blast.
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GMNoobFeb 14 '12 at 13:42

". the "pillar" occupies 1 square so its a 5x5x5 cube." Are you really trying to suggest that all PCs are 5x5x5 cubes?
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GMNoobFeb 14 '12 at 13:47

PCs are not 5x5x5 cubes, but they take up that amount of space for all intents and purposes. In general a PC would be taller than 5' and skinnier than 5'x5', but that is the closest distinct dimensional unit that they can occupy. As for the infinite z axis, are you saying that the Storm Pillar would hit a creature three miles up in the air, just because it happened to be in the same x and y position?
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Jason WhiteFeb 14 '12 at 15:24

1

@GMNoob: if two creatures could never have the same (x,y) coordinates, how would you handle a dragon flying over an army? Or a beholder hovering over an adventuring party? I've always run my games according to the dogma "side view == top view" regarding to occupation of space, reach, determining cover, and so on (unless the rules explicitly said something else, e.g. high jump).
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arotterFeb 14 '12 at 18:47